Question

Questions 5 and 6 concern the Motorola 68HC11 microcontroller that has an internal analogue- to-digital converter powered up by writing to the OPTION register and then initiated by writing to the ADCTL register. Bit 7 6 5 43 2 0 ADCTL register $1030 CCF SCAN| MULT CD | CC | CB | CA Conversion complete flag 1not complete 0 = complete Channel conversion select bits Multiple-channel/single-channel control 0 = perform 4 consecutive conversions Continuous scan control on a single channel 0 1 = perform 4 conversions on four one cycle of 4 conversions each time ADCTL is written to channels consecutively 1 = continuous conversions With MULT = 0 With MULT= 1 CD CA Channel converted PEO PE1 PE2 РЕЗ PE4 PE5 PE6 PE7 CB CD CB CA ADR1 ADR2 ADR3 ADR4 PEO PE1 PE2 PE3 PE4 PE5 PE6 PE7 Brief Explanation: 5. (page 381) To give four successive A/D conversions on a single channel, register ADCTL has written to it A 0001 1110 В 0000 01 11 С 00010000 D 0001 0111 Brief Explanation:_ 6. (page 381) To give four conversions on four consecutive channels PE4, PE5, PE6 and PE7, register ADCTL has written to it A 0000 0000 В 0000 0111 С 00010000 D 0001 0111

Answer 1

Answer :- 5) Option B is the correct answer. To make four A/D conversions on a single channel, bit 4 of ADCTL register must be zero. Thus option B has fourth bit as zero as 0000 0111.

Answer :- 6) Option D is the correct answer. For this, bit 4 must be 1, bit 3 must be zero and bit 2 must be one. This is found in option D only as 0001 0111.